And charles h



(No Model.)

J. L. OLA-3 0. H. O'ULVER & JVH. STRATTON.

APPARATUS FOR,- THREADING, PIPE FITTINGS.

No. 420,189. Patented JaJn. 28, 1390.

Witneaaea:

m V A m E L wk aw Ma Ja Jam 6 011.. flirat UNITED STATES ATENT OFFICE.

JOSHUA L. CLARK, OF PITTSBURG, PENNSYLVANIA, AND CHARLES H. OULVER AND JAMES H. STRATTON, OF AKRON, OHIO.

APPARATUS FOR TH READING PIPE-FITTINGS.

SPECIFICATION forming part of Letters Patent No. 420,189, dated January 28, 1890.

Application filed December 27, 1888. Serial No. 294,794. (No model.)

To all whom it may concern:

Be it known that we, JOSHUA L. CLARK, CHARLES H. OULvER, and JAMES H. STRAT- TON, citizens of the United States, residing, respectively, the first at Pittsburg, in the county of Allegheny and State of Pennsylvania, and the others at Akron, in the county of Summit and State of Ohio, have invented a certain new and useful Apparatus forBoring and Threading Pipe-Fittings, of which the following is a specification. 1

Our invention relates to improvements in taps for threading pipes and pipe-couplings wherein the couplings have a larger and smaller sockets disposed in pairs with their axes in alignment.

The objects of our invention are to provide means for threading the larger and smaller sockets by a continuous or practically simultaneous operation, and to avoid all liability of breakingthe socket-threads after they have been formed.

To the above purpose our invention consists in the novel construction and arrangement of the taps for threading the sockets, as hereinafter described, and specifically pointed out in the claim.

In order that our invention may be fully understood, we will proceed to describe it in detail with reference to the accompanying drawing, forming a part of this specification, and in which the figure is a side elevation of the tap for threading the socket.

In order to screw-thread the class of sockets before referred to, we have devised .the structure shown in the figure, in which- G design ates the stem of the tap, one end of which is provided with two thread-cutters G G, the former being of greater diameter than the latter, and the pitch of the thread 4 being alike in both. The stem Gworks within a hollow sleeve H, and at its inner'end carries a stud K, which works in an elongated slot K in sleeve H. A spiral spring S surrounds the sleeve H and abuts at one end against a 4 collar H on the corresponding end of sleeve H. The opposite end of spring S abuts against the stud K of the tap and tends to draw the stem G within the sleeve H, They (the sockets) are relieved of the weight of the tap 0 and all tendency toward rupturing the socketthreads is avoided. A tapered shank H" is formed upon the opposite end of the sleeve H from its collar H, and serves as the means for attaching the tap to the operative parts of the drill-press.

Having thus described ourinvention, what we clairn as new therein, and desire to secure by Letters Patent, is-

The combination of the threading-tap with its larger and smaller thread-cutter, the sleeve with its slot, and the counterbalancing-spring, substantially as shown, and for the purpose specified.

In testimony that we claim the above we hereunto set our hands.

JOSHUA L. CLARK. CHARLES H. OULVER. JAMES H. STRATTON. 

